The present invention relates to a starter for an internal combustion engine for a motor vehicle.
More specifically, the invention relates to a starter of the type including:
a movable pinion which is adapted to mesh with a gear of the internal combustion engine,
a control electromagnet including a core which is movable between a rest position and an actuating position and has an entrainment appendage at its end,
a transmission between the core of the electromagnet and the pinion, the transmission including a rocker lever with a first end connected to a movable member for moving the pinion and a second end which is connected, with play, to the appendage of the core of the electromagnet so that, when the electromagnet is excited, the core leaves its rest position and travels an initial distance without a load before the appendage pivots the lever, and
an electric motor which can be supplied so as to rotate the pinion when the movable core of the electromagnet has reached the actuation position and closes an electrical switch.
A starter of this type is described, for example, in French patent FR-B-2,587,760.
In starters of this type, the pinion must already be meshed with the ring gear of the internal combustion engine when the core of the electromagnet reaches the actuation position and the electric motor is supplied. This is necessary in order to prevent harmful slippage and consequent damage to the teeth of the pinon and of the ring gear when the motor is started.
The transmission between the core of the electromagnet and the pinion is not generally rigid. In fact, there is play in the connection between the rocker lever and the entrainment appendage of the electromagnet. The play is for preventing the pinion from accidentally being moved towards and against the ring gear of the internal combustion engine as a result of vibrations and jolting of the motor vehicle whilst the internal combustion engine is in operation and the starter is at rest.
As stated above, the transmission between the core of the electromagnet and the pinion is not rigid and may include one or more springs, for example, for facilitating the meshing between the pinion and the ring gear of the internal combustion engine in the event of frontal sticking. Moreover, the rocker lever itself is often resiliently flexible.
As a result of the play between the entrainment appendage of the core of the electromagnet and the rocker lever at rest, and of the fact that the transmission as a whole is not rigid, the movement of the pinion is not exactly proportional to that of the core. The pinion is not therefore always certain to be meshed adequately with the ring gear of the internal combustion engine when the core reaches the actuation position and the electric motor is supplied.
An object of the present invention is therefore to provide a starter of the aforesaid type which can reduce or prevent the problem described above.